Systems and methods for high intensity focused ultrasound

Abstract

Features for high intensity focused ultrasound (HIFU) are described. The application of HIFU for ablating tissue may be monitored in real time by imaging bubbles generated during HIFU. A single transducer array may be used by fast switching between imaging and HIFU. For imaging, the array or portions thereof may be used in receive only mode to locate bubbles generated by the HIFU. The application of HIFU, such as location and/or intensity, may be adjusted based on information from the imaging of the bubbles. Physicians and/or others may use these systems and methods to monitor HIFU procedures in real-time for optimal ablation of target tissue with minimal damage to healthy tissue.

1 . (canceled) 
     
     
         2 . A method for monitoring high intensity focused ultrasound (HIFU) ablation, the method comprising:
 repeatedly switching an ultrasonic transducer of an array of ultrasonic transducers between (a) applying HIFU to tissue within a body and (b) imaging a bubble generated due to the HIFU applied to the tissue, wherein the ultrasonic transducer of the array is used for both the applying HIFU and the imaging the bubble; and   determining a measure of HIFU efficacy based on the imaged bubble, wherein the applying HIFU comprises applying HIFU to the tissue based on the measure of HIFU efficacy.   
     
     
         3 . The method of  claim 2 , further comprising generating an indication of the imaged bubble that is indicative of progress of ablation associated with the applying HIFU. 
     
     
         4 . The method of  claim 3 , wherein the applying HIFU comprises applying HIFU to the tissue based on the measure of HIFU efficacy and on the generated indication of the imaged bubble that is indicative of progress of ablation. 
     
     
         5 . The method of  claim 3 , wherein generating the indication of the imaged bubble comprises determining a location of the bubble based on the imaging of the bubble. 
     
     
         6 . The method of  claim 2 , wherein the imaging the bubble comprises imaging bursting of the bubble. 
     
     
         7 . The method of  claim 2 , further comprising determining a stiffness of the tissue. 
     
     
         8 . The method of  claim 2 , wherein the ultrasonic transducers are capacitive micromachined ultrasonic transducers (CMUTs). 
     
     
         9 . The method of  claim 2 , further comprising repeatedly switching between applying the HIFU and imaging the bubble using a plurality of additional switches coupled with the array. 
     
     
         10 . The method of  claim 2 , wherein the repeatedly switching comprises switching to applying the HIFU after imaging the bubble in no more than two milliseconds. 
     
     
         11 . The method of  claim 10 , wherein the repeatedly switching comprises switching to applying the HIFU after imaging the bubble in no more than one millisecond. 
     
     
         12 . The method of  claim 11 , wherein the repeatedly switching comprises switching to applying the HIFU after imaging the bubble in no more than one microsecond. 
     
     
         13 . The method of  claim 3 , wherein the indication of the imaged bubble represents one or more of the following: a size of the bubble, a location of the bubble, a shape of the bubble, an emitted frequency of the bubble, a time of formation of the bubble, or a time of collapse of the bubble. 
     
     
         14 . The method of  claim 2 , wherein the tissue comprises at least a portion of a prostate with benign prostatic hyperplasia or at least a portion of a uterine fibroid. 
     
     
         15 . The method of  claim 2 , further comprising repeatedly switching a subset of ultrasonic transducers of the array of ultrasonic transducers between (a) applying HIFU to tissue within the body and (b) imaging one or more bubbles generated due to the HIFU applied to the tissue, wherein the subset of ultrasonic transducers of the array are used for both the applying HIFU and the imaging the one or more bubbles. 
     
     
         16 . The method of claim  25 , further comprising repeatedly switching all ultrasonic transducers of the array of ultrasonic transducers between (a) applying HIFU to tissue within the body and (b) imaging one or more bubbles generated due to the HIFU applied to the tissue, wherein all ultrasonic transducers of the array are used for both the applying HIFU and the imaging the one or more bubbles. 
     
     
         17 . A system for monitoring of high intensity focused ultrasound (HIFU) ablation, the system comprising:
 an array of ultrasonic transducers;   a switch coupled with the array, the switch configurable into at least a HIFU mode and an imaging mode; and   a processing circuit in communication with the array and the switch, the processing circuit configured to:
 control the switch to toggle an ultrasonic transducer of the array between the HIFU mode and the imaging mode, wherein the system is configured to apply HIFU to tissue using the ultrasonic transducer in the HIFU mode, and wherein the system is configured to image a bubble using the ultrasonic transducer in the imaging mode, the bubble being generated due to the HIFU applied to the tissue; and 
 determine a measure of HIFU efficacy based on the imaged bubble, wherein the system is configured to apply HIFU to the tissue using the ultrasonic transducer in the HIFU mode based on the measure of HIFU efficacy. 
   
     
     
         18 . The system of claim  27 , wherein the processing circuit is further configured to generate an indication of the imaged bubble that is indicative of progress of ablation associated with the applying HIFU. 
     
     
         19 . The system of  claim 18 , wherein the applying HIFU comprises applying HIFU to the tissue based on the measure of HIFU efficacy and on the generated indication of the imaged bubble that is indicative of progress of ablation. 
     
     
         20 . The system of  claim 18 , wherein the indication of the imaged bubble represents one or more of a size of the bubble, a location of the bubble, a shape of the bubble, an emitted frequency of the bubble, a time of formation of the bubble, or a time of collapse of the bubble. 
     
     
         21 . The system of  claim 17 , wherein the processing circuit is further configured to control the switch to change the ultrasonic transducer of the array between the HIFU mode and the imaging mode in no more than two milliseconds.